601 research outputs found
Electrochemical Formation of Germanene: pH 4.5
Germanene is a single layer allotrope of Ge, with a honeycomb structure similar to graphene. This report concerns the electrochemical formation of germanene in a pH 4.5 solution. The studies were performed using in situ Electrochemical Scanning Tunneling Microscopy (EC-STM), voltammetry, coulometry, surface X-ray diffraction (SXRD) and Raman spectroscopy to study germanene electrodeposition on Au(111) terraces. The deposition of Ge is kinetically slow and stops after 2–3 monolayers. EC-STM revealed a honeycomb (HC) structure with a rhombic unit cell, 0.44 ± 0.02 nm on a side, very close to that predicted for germanene in the literature. Ideally the HC structure is a continuous sheet, with six Ge atoms around each hole. However, only small domains, surrounded by defects, of this structure were observed in this study. The small coherence length and multiple rotations domains made direct observation with surface X-ray diffraction difficult. Raman spectroscopy was used to investigate the multi-layer Ge deposits. A peak near 290 cm^(−1), predicted to correspond to germanene, was observed on one particular area of the sample, while the rest resembled amorphous germanium. Electrochemical studies of germanene showed limited stability when exposed to oxygen
The MINERA Data Acquisition System and Infrastructure
MINERA (Main INjector ExpeRiment -A) is a new few-GeV neutrino
cross section experiment that began taking data in the FNAL NuMI (Fermi
National Accelerator Laboratory Neutrinos at the Main Injector) beam-line in
March of 2010. MINERA employs a fine-grained scintillator detector capable
of complete kinematic characterization of neutrino interactions. This paper
describes the MINERA data acquisition system (DAQ) including the read-out
electronics, software, and computing architecture.Comment: 34 pages, 16 figure
The Future of High Energy Physics Software and Computing
Software and Computing (S&C) are essential to all High Energy Physics (HEP)
experiments and many theoretical studies. The size and complexity of S&C are
now commensurate with that of experimental instruments, playing a critical role
in experimental design, data acquisition/instrumental control, reconstruction,
and analysis. Furthermore, S&C often plays a leading role in driving the
precision of theoretical calculations and simulations. Within this central role
in HEP, S&C has been immensely successful over the last decade. This report
looks forward to the next decade and beyond, in the context of the 2021
Particle Physics Community Planning Exercise ("Snowmass") organized by the
Division of Particles and Fields (DPF) of the American Physical Society.Comment: Computational Frontier Report Contribution to Snowmass 2021; 41
pages, 1 figure. v2: missing ref and added missing topical group conveners.
v3: fixed typo
Single neutral pion production by charged-current interactions on hydrocarbon at 3.6 GeV
Single neutral pion production via muon antineutrino charged-current
interactions in plastic scintillator (CH) is studied using the \minerva
detector exposed to the NuMI low-energy, wideband antineutrino beam at
Fermilab. Measurement of this process constrains models of neutral pion
production in nuclei, which is important because the neutral-current analog is
a background for appearance oscillation experiments. The
differential cross sections for momentum and production angle, for
events with a single observed and no charged pions, are presented and
compared to model predictions. These results comprise the first measurement of
the kinematics for this process.Comment: 6 pages, 5 figures, submitted to Physics Letters
First evidence of coherent meson production in neutrino-nucleus scattering
Neutrino-induced charged-current coherent kaon production,
, is a rare, inelastic electroweak process
that brings a on shell and leaves the target nucleus intact in its ground
state. This process is significantly lower in rate than neutrino-induced
charged-current coherent pion production, because of Cabibbo suppression and a
kinematic suppression due to the larger kaon mass. We search for such events in
the scintillator tracker of MINERvA by observing the final state ,
and no other detector activity, and by using the kinematics of the final state
particles to reconstruct the small momentum transfer to the nucleus, which is a
model-independent characteristic of coherent scattering. We find the first
experimental evidence for the process at significance.Comment: added ancillary file with information about the six kaon candidate
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